The training camp was held in secrecy at the derelict 208-acre Belcamp College site, situated off the Malahide Road in Dublin.

All gates to the complex were locked and seven garda vans were used to shield some 40 officers from public gaze as they underwent a series of intensive drills throughout the day.

The training included running a gauntlet of petrol bombs while in full riot gear, as well as baton charges and defensive manoeuvres.

The Sunday Independent has learned that the Public Order Unit, popularly known as the riot squad, will be on standby as thousands of protesters are expected to converge on the Dail in a protest organised by the Right to Work campaign this Tuesday.

Investigations are continuing into the disturbance at the gates of Leinster House in Dublin last week in which a number of people received minor injuries after the march attended by 800 people turned ugly.

A small number of protesters, believed to be linked to far left and hardline republican groups, attempted to gain access to the Leinster House complex but were prevented from doing so by uniformed gardai who drew batons.

A group of about 80 protesters broke away from the main group and attempted to storm the Dail gates. The group included members of Republican Sinn Fein, the socialist-republican group Eirigi and the Socialist Workers Party.

The most recent report from the International Monitoring Commission said that while Eirigi was a political group with a focus on aggressive protest rather than a paramilitary group, some members might have been involved in serious violence. "We do not believe that its leaders direct acts of terrorism but we note its ambiguous attitude towards the use of physical force, which it has not condemned," it said.

Although senior gardai accept that the vast majority of protesters last week were peaceable, they are worried about Tuesday's protest being hijacked by militant hardliners -- and extra precautions will be taken. At least five protesters and one garda received minor head injuries as a result of the clashes last week.

It is not thought that last Wednesday's intensive training camp was directly linked to the disturbances the previous evening.

SO YOU THINK YOU WANT A REVOLUTION? ANALYSIS, PAGE 29

But events in Greece, where riots sparked by harsh austerity measures left three bank workers dead and brought chaos and violence to the streets of Athens, has brought the issue of violent street protests into sharp focus across Europe.

Around 40 gardai were brought to the Belcamp College complex in lightly armoured garda vans early on Wednesday.

Wearing full body armour and riot helmets and carrying riot shields, the officers practised tactics designed to control and disperse large groups of protesters.

A garda source told the Sunday Independent that it was likely the training camp was arranged by garda top brass some time ago.

"The Public Order Unit has mostly been used in recent times at the Shell to Sea Corrib Gas protests in Co Mayo. Refresher courses are held on a fairly regular basis," he said.

The Public Order Unit was last seen in full operational mode in the centre of Dublin during the 2006 O'Connell Street riots, in which a number of officers were injured. In July 2008, members of the Public Order Unit along with the Air Support Unit and Dog Unit assisted local gardai when a feud between two Traveller families escalated into a riot lasting several hours in Dalton Park in Mullingar.

The Right to Work campaigners say they are expecting a much larger gathering at the Dail on Tuesday than the 800 who attended last week's demonstration.

James O'Toole from the Right to Work campaign said: "We have been inundated with expressions of support and expect a much larger gathering. The demonstration will be entirely peaceful and we will have plenty of stewards to cope with the numbers. Our aim is to build a broad-based mass movement that gets across the message to this Government that it has to go.

"It has no mandate to bail out banks while presiding over a return to mass emigration and unemployment," he said.

The Socialist Workers Party says it wants to "bring the spirit of Greece" to Ireland.

Yesterday, seven people were arrested at a protest at Anglo Irish Bank's headquarters in Dublin.

A banner was unfurled on the roof of the building's foyer at St Stephen's Green during the demonstration, which involved members of the republican group Eirigi.

All seven were taken to Pearse Street garda station where they were questioned in relation to alleged public order offences.